Fly Whose Wings Mimic Ants

taken by Peter Roosenschoon

The Goniurellia tridens (a fruit fly in the family Tephritidae) displays an amazing adaptation of markings on its wings that look like flies. There are many conflicting theories as to what advantage this gives the fly...

Dr Brigette Howarth believes that when threatened, the fly flashes its wings to give the appearance of ants walking back and forth, confusing the predator and allowing the fly time to escape. Howarth also suggest a sexual function, that perhaps the ant-like markings are involved in the complex routine of the flies mating ritual.

A different theory suggests the pattern may be a representation of jumping spiders, a predator of the fruit flies, which upon seeing the markings mistakes them for another spider of its species and displays to it, alerting the fly to its presence so it can escape. However, there already exist flies with much clearer spider-mimicking wings that are far more distant relatives of the Goniurellia tridens than flies with more randomly patterned wings, such as the Campiglossa albiceps. Perhaps there is not a strong enough evolutionary link between these different flies to relate their evolved wing patterns.

taken by Drew Gardner

Perhaps we are choosing to see ants because that is what we want to see, in the same way that we see a dragon in the clouds or Jesus on our toast. Whether or not the ant markings have evolved due to a selective advantage, it is incredible to think that random and accidental genetic mutations over a long period of time can result in an ornate pattern that is perfectly shaped to look like another insect.